To provide a flange for container such as a barrel and, a manufacturing method thereof wherein an uniform coat of a plating or a painting is applied even to a collar peripheral bottom edge part of a flange for a container such as a barrel for preventing the contents of the container from being contaminated with a plating chip or a painting chip by making the coat of the plating or painting at a flange fitting part inner surface of the barrel not coming off when a plug is opened/shut.

This flange 1 for a container such as a barrel is provided with a collar part 3 which is polygons seeing from the plane at the bottom edge of a cylindrical part 2 having female screws 4 on an inner surface and, a peripheral bottom part 3a of the collar part 3 is made of a curved surface in almost circular arc shape in its cross section. As to a manufacturing method of the flange, an inner circular bottom edge of a collar part accommodation concave part, which being polygonal seeing from a bottom die 12 plane of a die 11, is made of a curved surface almost circular arc shape in its cross section, and the flange collar part 3 before performing a finish mold is put in the bottom die concave part. The collar part 3 is then pressurized with the upper die so that the right angular shape peripheral bottom edge part 3a in cross section of the collar part 3 is finish-molded in almost circular arc shape in its cross section.